Electronic chassis typically include a plurality of circuit board assemblies. Each circuit board assembly is comprised of at least one printed circuit board that is attached to C-shaped channel member that serves as the faceplate for the assembly. The printed circuit board typically includes at least one surface mounted connector (such as, for example, an F-series connector). The channel member typically has at least one opening therein to allow a portion of the connector to extend through the opening in the bracket to enable a technician to plug an input cable or cord into the connector.
When the connector is inserted through the opening in the channel, the gap around the opening in the bracket must be properly sealed to prevent electromagnetic radiation generated by the electronic components of the printed circuit board from exiting through the channel. Excessive electromagnetic interference (EMI) is a widespread problem in many electronic devices, especially in high-speed telecommunication and networking applications. These electronic devices must meet very stringent emissions standards in the United States and in other foreign countries.
Shielding components are available which can be used to reduce EMI emissions that exit through an opening formed in the channel member. Typically, a flat metal nut is positioned over the connector on the outer surface of the channel member, and is mechanically attached to the channel. There are several disadvantages to this arrangement, including increased manufacturing costs associated with having to use fastening tools to manually fasten these nuts to the channel. The installation of these nuts with fastening tools may also create unacceptable loads on the solder joints of the connectors, which may cause the joints to fail. Moreover, rigid metal nuts do not provide any flexibility to compensate for components that are out of tolerance, which may result in excessive amounts of electromagnetic radiation exiting the assembly through gaps formed between the components.
In addition, flat metal nuts typically occupy a considerable amount of space on the outer surface of the channel, which limits the number of available input/output connections and the amount of artwork on the outer surface. Also, the outer surface of the channel must be masked before painting to ensure that there is metal to metal contact between the nut and the surface of the channel. Once installed, the nut itself typically has to be painted to match the color of the outer surface. This two step painting process also increases manufacturing costs.
Accordingly, it would be desirable to have an EMI shielding apparatus that overcomes the disadvantages described above, and to provide a simple and cost effective EMI shielding apparatus.